Percussion drilling tool



March 28, 1967 s. COLLIER L 3,311,177

PERCUSSION DRILLING TOOL Filed Aug. 5, 1966 3 SheetsSheet l INVENTORS Jamue/ Z. (0 ///e/* ATTO/M/EV 2 .2 M f e a m l d an .A/ w 32 N v. m iv h m S 3 Z L h 1 emW g V, Z

Mam}! 1967 s. L. COLLIER ETAL PERCUSSION DRILLING TOOL D r t l 1 gu k Filed Aug. 5, 1966 March 28, 1967 S. L COLLIER ETAL 37311,?

PERCUSSION DRILLING TOOL Filed Aug. 5, 1966 3 Sheets-Sheet 5 30.6 f z-m z /A 3d a V g I 29c 2447 A i INVENTORS Ja/Wue/ Z. (o/her 8 Y War V? f. Jcv/m w K V ,7 f

11 FT DRIVE Y United States Patent 3,311,177 PERCUSSISN DRILLING TOOL Samuel L. Collier and Marvin E. Schindler, both of Houston, Tern, assignors to Mission Manufacturing Company, Houston, Tex., a corporation of Texas Filed Aug. 3, 1966, Ser. No. 575,212 8 Claims. (Cl. 173133) This is a continuation-in-part of our copending application Ser. No. 381,840, filed'luly 10, 1964. This invention relates to percussion drilling tools and consists particularly in novel blowing means whereby the main volume of pressured working fluid may be bypassed directly to the exhaust duct extending through the cutting implement when the tool is suspended off bottom.

A difliculty with prior art percussion tools having similarly functioning blowing means is that, usually, the working chamber within which the hammer piston reciprocates is exposed during the blowing periods to the pressure of the working fluid. This may have the effect of continuing operation of the piston even though the tool is suspended ofl bottom (tapping). Consequently, with the use of such tools, it has been necessary, in order to prevent such tapping, to additionally vent the forward pressure chamber or to first cut off the supply of pressured working fluid, as the tool is lifted from the bottom of the hole, and then restart the supply to clean out the hole.

In Patent No. 3,105,559, issued Oct. 1, 1963, in the names of Samuel L. Collier and Melton L. Ply, there is shown a percussion drilling tool of the type having a we ing forming a working chamber within which the hammer piston reciprocates and also having an axial porting stem extending therethrough from the Working pressure connection at the rear end of the casing. An anvil member, usually a combination anvil-bit, is slidably received in the forward end of the casing and has a central exhaust duct in which the forward extremity of the porting tube is slidably received. A blowing port near the forward extremity of the tube is covered by the wall of the anvil duct, during normal on-bottom operation, but is uncovered when the tool is suspended oif bottom so that the pressured Working fluid flowing into the forward end of the working chamber now may escape through the blowing port and thence into the anvil duct. With this arrangement it has been found in some cases that tapping of the piston occurs during the blowing period.

Consequently, it is an object of the present invention to provide an improvement upon the percussion tool of the general type illustrated in the Collier et al. patent and in which the blowing port is positioned to be sealed by the anvil during normal operation, yet is not exposed to the operating chamber when the tool is supported oif bottom.

Another object is to provide an improved anvil-bit device for use with a percussion drilling tool of the general type illustrated in the Collier et al. patent.

Another object is to provide means for exhausting the working chamber during oif-bottom operation with the working fluid being bypassed directly into the anvil exhaust duct.

According to the present invention, the portion of the anvil exhaust duct within which the forward end of the porting tube is slidably received is provided with a recess which is so shaped and positioned that when the anvil advances abnormally with the tool suspended olf bottom, substantially the full volume of working fluid is directed by the blowing port through the recess and thence into the exhaust duct. This is facilitated in the present invention by the location of the constant bypass choke downstream of the blowing port instead of upstream thereof, as in the mentioned Collier et al. patent.

Patented Mar. 28, 196? In a second form of the invention, a special exhaust port in the forward or downstream end of the porting tube is cleared by the anvil, with the tool suspended off bottom, for insuring exhausting of the working chamber. In the accompanying drawings which illustrate the invention:

FIG. 1 is a schematic elevation and section showing the novel tool introduced in a well bore;

FIGS. 2A and 2B are longitudinal center sections, re-

spectively, of the upper and lower portions of the tool on a substantially enlarged scale, FIG. 23 showing portions broken away to illustrate the underlying structure;

FIG. 3 is a longitudinal detail section, similar to FIG. 2B, but showing the parts in a different position;

FIG. 4 is an enlarged transverse section taken substantially on line 44 of FIG. 3;

FIG. 5 is an enlarged transverse section taken one half on line 55 of FIG. 3 and one half on line 5-5 of FIG. 2A;

FIG. 6 is a view similar to FIG. 3 and showing a modified tool in suspended, off-bottom position; and

FIG. 7 is a view similar to FIG. 2B and showing another modified tool in normal, on-bottom operation.

The tool, generally designated 5, is supported in operative position in a drill hole 6 by means of a drill string 7, as in quarrying or well drilling operations. Any suitable means for manipulating the drill string may be provided on rig table 3. The tool includes, broadly, a sub 9 (FIG. 2A) forming a connection for the pressured working fluid between the drill string and the working chamber 16 within the casing 11. Slidably received within the lower or forward end of the working chamber (FIG. 2B) is the anvil-bit device, generally designated 12, which includes an intermediate shank portion 13 and a suitable cutting tool or bit 14 at its lower extremity. The generally cylindrical upper portion 15 of the anvil-bit device is slidably received in the lower or forward extremity of casing 11. An exhaust duct 16 extends axially through the anvil-bit for discharge about the cutters to clean out the hole in the usual manner. A driver sub or chuck 17, conveniently split, is threadedly mounted in the end of casing 11 and is provided with splineways 18 registering with splineways 19 in the external surface of anvilbit shank 13 for receiving bridging rollers 26 which enforce joint rotation of the casing and anvil-bit while permitting the anvil-bit to slide axially with respect to the casing. The bottom of chuck 17 rests on a shoulder 14a on the bit to limit the entry of the anvil into the casing and establish the normal Working positioning of the parts. A shoulder 15a on the upper part of the anvil engages top of chuck 17 (FIG. 3) to limit the dropping of the anvil relative to the casing.

Supported in upper or rear sub 9 and extending axially through the working chamber is a porting tube, generally designated 21. As best shown in FIG. 5, this tube is made up of an external sleeve 22 and a fluted and drilled core 23 sealingly lodged therein. Extending axially through the core is a passage 24 communicating at its upper (rear) end with the interior of the drill string and partially closed at its bottom end by a plug 25 in which there is provided a small hole (choke) 26 for constantly bypassing a part of the working air into exhaust duct 16. A pair of main pressure ports 27 extend from the mid portion of passage 24- through the wall of the tube. The core is segmentally flattened at opposite sides, along substantially its entire length, to form exhaust passages 28 which open at their lower ends into exhaust duct 16 (FIG. 4). Pairs of upper and lower exhaust ports 29 and 29a are provided in sleevel 22 for connecting exhaust passages 23 to the opposite ends of working chamber 19. Also formed in core portion 23 of the porting stem are pairs of aligned flutes' 3 30 and 31, each pair being aligned with one of the main pressure ports 27 and separated therefrom by lands 32 on the stem.

A hollow piston 34 reciprocates within working chamber when working pressure is supplied to main pressure port 27, as will be explained, so as to beat upon the upper end of anvil element 15. The piston has a central shuttle recess 35 which always communicates with main pressure port 27 in the porting tube. Flutes 3G and 31 of the porting tube alternately direct the pressured working fluid from shuttle groove 35 to the opposite ends of the working chamber through ports 36, 37, 38, and 39.

At the lower or forward extremity of the porting tub-e there are provided one or more laterally-opening blowing ports 40 adjacent end plug 25. The forward extremity of the porting stem is snugly though slidably received in and normally engages spaced wall portions 41 and 42 of anvil duct 16 so that blowing ports 40 are sealed (FIG. 2B). Between these wall portions there is provided an annular recess 43 which constitutes a special configuration of the anvil-bit device for use in the particular percussion tool illustrated.

In operation of the tool, with the cutting implement 14 resting on the bottom of the bore hole, as illustrated in FIGS. 1 and 2B, the supply of pressured working air is turned on. This air passes through main pressure port 27 into shuttle groove 35 in the piston. With the piston in its lower or forward position, as it will be when operation is started, the working air passes through shuttle groove 35 and lower flutes in the porting stem to the forward end of the working chamber. The upper edge of the piston will clear exhaust port 29 and the upper or rearward end of the working chamher will be exhausted through ports 29 and passages 28 and the piston will rise. Shortly after the piston begins to rise, the lower edge of shuttle groove passes above ports 39 cutting off lower flutes 30, and thereafter, the charge in the forward pressure chamber expands to continue the upward movement of the piston. Near the end of the upward stroke, the lower edge of the piston uncovers lower exhaust ports 29a which permits the forward end of the working chamber to exhaust through passages 28 and duct 16. At approximately the same time, shuttle recess 35 communicates with upper flutes 31 through ports 36 to direct the working fluid through ports 37 into the rear or upper end of the working chamber. The piston is then driven downwardly and strikes the anvil.

Reciprocation of the hammer piston 34 will continue Within its normal range as long as the pressured working fluid is supplied to the upper end of the porting stem and the tool remains on bottom. In case an extra supply of air is required for cleaning out the hole, the tool may be lifted off bottom to permit the anvil-bit 12 to drop abnormally to the position shown in FIG. 3 resting upon the upper end of chuck 17. In this position, blowing ports .0 which, during normal operation, are abreast of and sealed by duct wall portion 41 downstream of annular recess 43, are now abreast of this recess. This recess is shaped so as to direct the supply of working fluid directly from tube passage 24 around the extremity of the porting stem and into anvil-bit duct 16 through ports as well as choke 26. At the same time, the piston drops sufliciently to close ports 38 at the lower ends of fines 30, stopping the flow of working fluid to the lower end of the working chamber. Thus, the blowing fluid is supplied to duct 16 and the bit entirely independently of the working chamber so that no pressure differential is applied to the piston and reciprocation or tapping of the motor piston is positively prevented as soon as the tool is lifted off bottom. If the supply of working fluid is continued, it is bypassed directly into the anvil-bit exhaust duct substantially at Working pressure.

In some cases, working fluid may leak into the lower working chamber during ofi-bottom blowing with resultant tapping, notwithstanding the intended sealing of ports 38 by the piston and segregation of exhaust duct 16 from the working chamber, by duct wall portion 42 upstream of recess 43. The modifications in FIGS. 6 and 7 are intended to cure this difliculty. Corresponding parts of these slightly modified tools are referenced with the same numerals as the first form with the suflix a (FIG. 6) or b (FIG. 7), except as noted. In FIG. 6, showing the tool hanging off bottom, exhaust passages 28a open into duct 16a through ports 50. Additional exhaust ports 51 (only one is shown) are provided through the walls of passages 28a in position to be closed by wall portion 42a of anvil duct 16, when the tool is operating normally on bottom (see FIG. 7), at the same time that blowing port 40a is closed by duct wall part 41a downstream of recess 43a. When the tool is suspended off bottom, as shown in FIG. 6, blowing port 40a is connected by recess 43a to exhaust duct 16a, as in the first form. At the same time, extra exhaust port 51 is cleared by the anvil and connects the lower operating chamber directly to exhaust.

In FIG. 7, which is at degrees to FIG. 6 and shows the tool operating normally on bottom, extra exhaust port 51a is positioned to be closed by anvil duct wall part 42b at this time and to be cleared by the anvil, when the tool is hanging off bottom (see FIG. 6), to exhaust the working chamber. Structural differences between the attachments of the casing and anvil in the three forms are recognizable, but not otherwise noted as they are not involved in the present invention. For instance, FIG. 6 shows no working fluid bypass 26 at the bottom of the porting stem, while FIG. 7 shows a normally-open float valve 52 in the bypass port 26b.

The invention may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

We claim:

1. A percussion drilling tool comprising a casing forming a working chamber, a connection at the rearward end of said chamber for pressured working fluid, an anvil element slidably received in the forward portion of said chamber and shiftable from a normal working position to an abnormally advanced position when the tool is supported off bottom, an exhaust duct in said anvil, a tube extending axially through said chamber from said connection and having an end portion slidably received in said duct, a sidewardly-opening blowing port in the wall of said tube portion and communicating with said connection through said tube, and a recess in the wall of said anvil duct abreast of said tube portion, the parts of the wall of said duct forwardly and rearwardly of said recess forming a snug running fit with said tube portion, said port, during normal on-bottom operation of the tool, being abreast of and substantially sealed by the more forwardly of said wall parts, said recess being abreast of said port when the tool is supported off bottom and being shaped to direct fluid from said port into said anvil duct, said rearward duct wall portion substantially sealing said recess and said port from said working chamber.

2. A percussion drilling tool as described in claim 1 further including a main pressure port and at least one exhaust port in the intermediate portion of said tube, a pressure passage and an exhaust passage in said tube, respectively, connecting said main pressure port and said connection and said exhaust port and said duct, and means including a shuttle recess in the inner Wall of said piston for alternately directing the working fluid from said main pressure port to the opposite ends of said working chamber and exhausting at least one of said chamber ends through said exhaust passage and said duct.

3. A percussion drilling tool as described in claim 1 in which said recess in said duct wall is of greater expanse axially of said duct than the distance between said blowing port and the adjacent end of said tube.

4. A percussion drilling tool as described in claim 1 further including a cut-ting tool on said anvil element.

5. An anvil device for use with a percussion drilling tool of the type having a casing, an axial tube for pressured working fluid, and a blowing port in the forward extremity of said tube, comprising a body for slidable reception in the forward end of the casing, an exhaust duct extending through said body, and a recess in the wall of said duct, there being wall portions of said duct forwardly and rearwardly of said recess shaped to snugly receive said tube portion during normal on-bottom operation of the tool, said recess being shaped to connect said port and said duct when the tool is supported off bottom.

6. An anvil-bit device for use with a percussion drilling tool of the type having a casing, an axial port tube with a blowing port in the forward extremity thereof, and a reciprocable hammer piston, comprising an anvil portion for slidable reception in the forward end of said casing for receiving the blows of said piston, and an exhaust duct extending axially through said device, there being a recess in the wall of said duct and said wall forwardly and rearwardly of said recess conforming closely with the external contour of said tube extremity, said recess being shaped to connect the said blowing port with said duct when said port is abreast of said recess with the tool supported off bottom.

7. A percussion drilling tool comprising a casing forming a working chamber, a connection at the rearward end of said chamber for pressured working fluid, an anvil element slidably received in the forward portion of said chamber and shiftable from a normal working position to an abnormally advanced position when the tool is supported otf bottom, an exhaust duct in said anvil, a tube extending axially through said chamber from said connection and having an end portion slidably received in said duct, a blowing port and first and second exhaust ports in the wall of said tube end portion, said blowing port communicating with said connection and said first exhaust port opening into said anvil exhaust duct, a conduit connecting said first and second exhaust ports, a recess in said duct wall, the duct wall portions downstream and upstream of said recess respectively being positioned to close said blowing port and said second exhaust port when said tool is operating normally on bottom, said recess being positioned to connect said blowing port to said exhaust duct for directing working fluid into said exhaust duct and said second exhaust port being positioned to clear said duct wall for exhausting said working chamber when said tool is hanging off bottom.

8. A percussion drilling tool as described in claim 7 in which said tube includes a working fluid passage, an eX- haust passage, and at least one additional exhaust port for exhausting said working chamber during normal, onbottom operation of the tool, said exhaust passage terminating in said first exhaust port.

References Cited by the Examiner UNITED STATES PATENTS 2,887,989 5/1959 Dulaney 17364 3,059,619 10/1962 Beumont 17364 3,105,559 10/1963 Collier et al 17373 3,225,841 12/1965 Thompson 17373 FRED C. MATTERN, JR., Primary Examiner.

L. P. KESSLER, Assistant Examiner. 

5. AN ANVIL DEVICE FOR USE WITH A PERCUSSION DRILLING TOOL OF THE TYPE HAVING A CASING, AN AXIAL TUBE FOR PRESSURED WORKING FLUID, AND A BLOWING PORT IN THE FORWARD EXTREMITY OF SAID TUBE, COMPRISING A BODY FOR SLIDABLE RECEPTION IN THE FORWARD END OF THE CASING, AN EXHAUST DUCT EXTENDING THROUGH SAID BODY, AND A RECESS IN THE WALL OF SAID DUCT, THERE BEING WALL PORTIONS OF SAID DUCT FORWARDLY AND REAR- 